This invention relates to pulsed-transmission, single frequency echo-ranging sonar systems, and more particularly to the array used to form the projected acoustic beam.
The principal object of this invention is to produce a nearly constant amount of acoustic energy throughout the desired vertical field of view (nominally 90 degrees).
A second object is to reduce or eliminate the amount of acoustic energy radiated in directions other than the desired field of view (cutoff region).
Another object is to cause a very rapid transition ("brick wall") from the desired field of view to the cutoff region.
Yet another object is to achieve the desired beam pattern improvement using an array with much less piezoelectric material than required by previous design methods.